There is known an operation input device having a structure in which a touch pad is provided on a movable operation part moved by a user to be operated (Patent Documents 1 and 2 below, for example). The area necessary for installation of an operation input device having such a structure suffices to be small, and thus the operation input device is effective for installation to a location where the installable position and area are limited, such as the vicinity of a driver's seat of a vehicle, for example.